The present invention relates to a method and apparatus for updating system configuration information, and more particularly, to a method and apparatus for determining physical configuration information and for assigning bus addresses to hardware components installed on equipment, such as a cell station.
Conventional cellular telephone systems include a central control station that interconnects the cellular telephone system with any suitable telephone switching system, such as the Public Switched Telephone Network (PSTN), and one or more cell stations. The cell stations are generally remote from the central control station and are typically placed throughout a cellular telephone service area. Telephone calls may be selectively placed by the central control station between standard land line telephone subscribers of the PSTN and a cellular telephone unit or directly between two cellular telephone units, in a known manner. For a more detailed description of a suitable cellular telephone system, see, for example, U.S. Pat. No. 4,829,554, incorporated by reference herein.
In order for a cell station to perform required function, the cell station typically incorporates hardware components, often referred to as xe2x80x9ccircuit packs.xe2x80x9d The same cell station, for example, might include a set of transceivers and other hardware equipment, such as control and timing boards, for communicating with cellular telephone units in a known manner. In addition, a cell station can include one or more interface boards for communicating, for example, on a T1 line with a switch of the PSTN. In order for the cell station to properly communicate with and supervise each of the various hardware components, the cell station also includes a hardware controller. The hardware controller and each of the hardware components are typically stored by the cell station on a frame or rack.
In the event of a hardware component failure or when routine servicing is required, a given hardware component on a cell station might be replaced by a compatible piece of hardware, having a different manufacturer, model number or version. In addition, additional hardware components may be added to the cell station to increase the capacity of the cell station, or the cell station configuration may otherwise be modified. As each new hardware component is added to a cell station, the hardware component must typically be associated with a particular sector (antenna) and carrier frequency on the cell station.
Each hardware component typically communicates with the hardware controller and with one another on a common bus. In order to differentiate each hardware component on the common bus, each hardware component is assigned a unique address. The hardware controller maintains a directory that maps the sector and carrier frequency associated with each hardware component, as well as the corresponding bus address. The system configuration information stored by the hardware controller must match the physical hardware components that are actually installed on the cell station.
Some systems for determining system configuration information, however, including sector, carrier frequency and bus assignments for each hardware component, are labor-intensive and require considerable manual effort. Specifically, an operator typically manually enters the relationship between the physical address of each hardware component and the corresponding logical connection (sector and carrier frequency) for all hardware components installed on a given cell station. In addition, each slot often has a prewired address. When a hardware component is plugged into the slot, the hardware component reads the address value from the backplane and uses the address to communicate with other hardware components and the hardware controller on the common bus. Since the prewired backplane address has little or no physical location information, manually generated conversion information is needed to convert the backplane address to an understanding of the type of hardware component that is at that address, as well as the sector and carrier frequency associated with the hardware component.
As apparent from the above-described deficiencies with conventional techniques for obtaining system configuration information, a need exists for an automated technique for automatically determining system configuration information and for assigning addresses on a common bus.
Generally, according to one aspect of the invention, a method and apparatus are disclosed for automatically determining system configuration information, including the sector, carrier frequency and bus assignment of each hardware component installed on equipment, such as a cell station. In an illustrative cell station implementation, each cell station includes a hardware controller that communicates on a common bus with a plurality of hardware components.
Each hardware component reads an identification value that has some physical significance from a backplane on which the hardware component is installed. The physical identification value indicates how the hardware component is interconnected in a larger piece of equipment. In the illustrative embodiment, the physical identification value identifies the carrier frequency, frame, sector number (such as xcex1, xcex2, xcex3), unit type and unit number associated with the hardware component. The identification value may be set by hardwiring the value into the backplane, manually adjusting one or more dip switches, or a combination of the foregoing. In an alternate embodiment, the identification value may be programmatically set, for example, by the hardware controller.
Generally, each hardware component reads only a portion of the identification value from the backplane. For example, the hardware component generally knows its own unit type. In addition, some hardware components, such as a clock board, are common across all carrier frequencies and sectors in the cell station, so such global hardware components do not need to read the carrier frequency and sector fields of the identification value.
According to one aspect of the invention, the physical identification information obtained from the backplane is used by the hardware components to derive a bus address that uniquely identifies each hardware component on the common bus. When a cell station is powered up, each hardware component reads the corresponding identification value and determines a unique bus address for communicating on the common bus.
According to another aspect of the invention, the physical identification information obtained from the backplane conveys physical configuration information to the hardware components. Thus, the hardware component can report the physical configuration information to the hardware controller and allow the hardware controller to identify each hardware component and to determine how the various hardware components are interconnected. Thus, in an embodiment where the identification value for each hardware component is unknown to the hardware controller (for example, where the identification value is manually set by hardwiring the value into the backplane or by adjusting one or more dip switches), the hardware controller can generate a map or database of the hardware components located within the cell and determine their interconnection.
A more complete understanding of the present invention, as well as further features and advantages of the present invention, will be obtained by reference to the following detailed description and drawings.